Ionic discharge tube



April 23, 1935. J, E. HENDERSON ET AL 3,998,457

IONIC DISCHARGE TUBE Filed May 15, 1935 I f f INVENTORS I I 21, pUpuQuUuuub ATTORNEYS Patented Apr. 23, 1935 UNITED STATES PATENT OFFICE IONIC DISCHARGE TUBE poration Application May 15, 1933, Serial No. 671,231

14 Claims.

This invention relates to luminous ionic discharge tubes operable at ordinary commercial frequencies by means of which light practically like daylight can be obtained and in which the 5 spectra can be varied to suit the users requirements. The terminals or electrodes of the tube will remain cool for indefinite lengths of time without artificial cooling unless desired. Reference is hereby made to applicants prior applica- .0 tion Serial No. 521,177, filed March 9, 1931.

The surface area of the electrodeis made very large compared to its volume (ratio of surface to volume is very large) and is located on a large number of small electrode tubes that are con- .5 nected to headers which are in turn connected to another header for connection to the luminous portion of the tube. In this way condenser or dielectric electrodes are made up of sufficient capacitance to provide the desired illumination I without requiring an undue amount of space. In

view of the high capacitance due to the large electrode area of the device a transformer having a large percentage leakage reactance. is used in order that the power factor of the combined tube and transformer will be approximately unity.

There is no contact between the gas that is used inside the tube and conducting material that is applied to the outside of the electrodes at the terminals of the tube. Carbon dioxide or carbon monoxide is preferably used and may be mixed with one or more gases or vapors to provide spectra of the desired sort or to increase the efficiency.

- The invention will be understood from the ac-.

the body portion or luminous portion of an ionic discharge tube, only the ends thereof near the dielectric electrode terminals being shown. This tube may be made of diiferentlengths, sizes and-shapes andmaybe made of ordinary commercial glass, although it is preferably made of pyrex glassor other clearglass that is not easily.

, 3 the electrode tubes Bare spaced apart so that the cracked or broken.

An illustrative embodimentof an/electrode at Q an end of the luminous tubelJ will now be described. A glass header 2" is connected by the connection 3 to an end of the tube l. A series of spaced headers is connected by connectors 5 to the header 2 on alternate sides thereof in staggered relation, as shown in Figs. 1 and 2.

The tubes 6 are spaced apart slightly and the 10' groups of tubes 6 which are connected to the headers 4 are preferably located in parallel planes and are preferably installed so that there are vertical air passages between the tubes to facilitate cooling of them by the rising current of air.

A conducting coating 1 (Figure 3) 'is applied to the outside of each tube 6 over as large a portion thereof as is desired. This coating 1 may also be applied over all or as large a. portion as is desired, of the headers 2 and 4 and theconnections 3 and 5. Lacquer 8 may be applied to the outside of the coatings l to insulate the same and minimize static discharge.

Conductors or lead-in wires 9 may be wound around the glass of the electrodes before the conducting coating 1 is applied and then the lacquer 8 may be applied leaving the ends of the wire 9 exposed for convenience in connecting the coatings of the electrodes to the secondary terminals of the transformer which supplies the 3 0 power for illumination.

A transformer I0 is indicated inFig. 1 and is supplied by a source of alternating current II. The source of supply II is connected to the primary l2 of the transformer I0 and the secondary I3 of this transformer is connected by means of wires M to the lead-in wires 9 of the electrodes at the ends of the tube I. The transformer frame is indicated at I5 and iron cross pieces I Gmay be used for the purpose of providing the proper {40 amount of leakageof magnetic flux, thus compensating for the capacitance of theelectrodes-and providing as near unity power factor as is desired.

It has'been found in operating a dielectric elec trode luminous ionic discharge tube of this sort that if the glass at the terminals'is'heated too much it tends to lose its dielectric properties and if the temperature rises aboveabout 100 C. there islikelihood of the same puncturing and admit-. ting air to the tube. By the present invention circulation of the air about them keeps thetemperature below the danger point. Heat is produced on the inside ofthe' tubes 6 whilethe tube'. is in operation. The longer each tube 6 is the The connections of 5 more energy dissipated at a given voltage and frequency and the more heat developed in it and the greater likelihood of puncture. The heating effect increases toward the tube ends which are connected to the header 4. The electrode tubes may be run in more than one direction or plane from the header if desired. If desired, a header to which the tubes ,or tips 6 are sealed may have the end thereof turned at right angles and extend parallel to the tubes 6 and slightly beyond them, thus providing a support upon which the electrode may rest.

Greater condenser areas are obtainable in a given space with smaller diameter tubes, but with smaller cross sectional areas of tubes the heat produced is greater with equal currents. We have found that a luminous tube which will last many thousands of hours can be made as indicated in the drawing with electrodes made up, for example, of tubes 6 about eight inches long and five mm. outside diameter spaced apart about. 2 mm. when using the ordinary luminous tube transformer of 12,000 volt rating, the headers 4 being ten mm. outside diameter and spaced about fifteen mm. apart with the header 2 of eighteen mm. outside diameter and the connection 3 from the header 2 to the luminous tube of twenty mm. outside diameter. Palms made up of eight rows of eleven tubes 6 of this size in each row have been found to be adequate. However, the lengths and sizes of the tubes, as wellas the number and spacings maybe varied over considerable ranges. The thickness of the glass may be varied over considerable ranges, also. When thicker glass is used it permitshigher safe temperatures, but less current passes through it with the same dielectric area and same voltage, other conditions being constant. An ordinary luminous tube transformer of 12,000 volt rating at 60 cycles will pass '70 milliamperes of current through the electrodes described above, one on each end of 51 ft. 15 mm. diameter luminous tubing. Lower voltages cause smaller currents to pass through and higher voltages larger currents. With transformers rated at 2,000 to 9,000 volts longer .tubes 6 may be used and the spaces between the tubes reduced while with higher voltages the tubes 6 may be shortened or the spaces between them increased, or both, in order to maintain safe operating temperatures.

It is to be understood that the electrode conducting coating 1 is not confined to the tubes or tips 6, but that the headers to which these tips are connected may also be coated to form a portion of the electrode. Surfaces of larger electrodes and larger tips provide larger electrode areas so that more current may be delivered from them to luminous tubes than is possible with smaller headers and tips.

Carbon dioxide or carbon monoxide in the tube gives a light that matches clear north sky light. It is desirable to have the tube emit a light constant in spectrum and for the tube to have a long life. Modifications of the light may be obtained by filling the tube with mixtures of helium and carbon dioxide or other gases. In operation the light emitted by the mixture may appear to the eye to be white, although the spectrum contains increased red, red-orange and orange-yellow compared to. the light given oil? by pure carbon dioxide or carbon monoxide. The luminous efliciency of a helium and carbon dioxide mixture is greater than that of carbon dioxide alone. may be used to obtain different spectra.

Mixtures of other suitable gases It is necessary to remove all mechanical stress due to uneven heating in the assembly of the electrodes by carefully annealing the completed electrode. This is done in order to increase the mechanical strength of the electrode and to insure the even distribution of the electrical stresses which are set up when the tube is operating. This can be done by heating the electrodes slightly above 700 C. in the case of Pyrex, or the softening temperature of any other glass used, while the parts are supported so that they will not sag, and allowing the electrodes to cool slowly.

The conducting coating 1 should remain in close contact with the glass and should not be one that would corrode in use. Different conducting materials may be used for this purpose. Lead, for example, is suitable. The lead, which may contain small amounts of tin, may be applied by dipping the electrodes into a molten bath of lead at a temperature just above its fusing temperature. The lower the melting point of the conducting coating the less danger there is of introducing cooling strains in the glass, and the higher the melting point of the coating the less danger there is of its melting off when the tube is operated.

The lacquer coatings 8 are desirable because at voltages at about 9,000 or more static discharges take place without them, forming ozone and causing a noise. It has been found that a few coats of'lacquer decrease or obviate static discharges and prevent ozone from being formed 1 and also prevent oxidation of the coating when 1 made of metal.

It is to be understood that the dielectric electrode may be made as described above with the conducting material on the outside or with the conducting material on the inside of the dielectric and the gas on the outside of the dielectric and contained in a capsule or container. When conducting material is used on the inside it may be in the form of a plate that is fiat or spiral, for

example, and coated with Pyrex, porcelain or other dielectric of the required thickness.

We claim: I

1. A luminous ionic discharge tube comprising a multiplicity of small short electrode tubes at the terminals, headers to which said small tubes are connected and a tube for illumination to which said headers are connected each one of said electrode tubes being of smaller internal diameter than said tube for illumination.

2. A' luminous ionic discharge tube comprising a multiplicity of small short electrode tubes at the terminals, headers to which said small tubes are connected and a tube for illumination to which said headers are connected, said small tubes being coated on the outside with conducting material and being of smaller internal diameter than said tube for illumination.

3. A luminous ionic discharge tube comprising a. multiplicity of small short electrode tubes at the terminals, headers to which said small tubes are connected and a tube for illumination to which said headers are connected, said small tubes being coated on the outside with conducting material and being of smaller internal diameter than said tube for illumination, and insulating material surrounding said conducting material.

4. A luminous ionic discharge tube having an electrode made up of a series of rows of small electrode tubes and arranged to permit cooling air to pass between them.

5. In a luminous ionic discharge tube, an electrode comprising a multiplicity of small short tubes connected to a header, conducting material covering substantially the entire outside surface of said tubes, said tubes being in sets, a header for each set, and a tube for illumination to which said headers are connected.

6. In a luminous ionic discharge tube, an electrode comprising a multiplicity of small, short tubes of dielectric material with conductive material on one side of the dielectric and gas on the other side thereof, said tubes being in sets, a header for each set, and a tube for illumination to which said headers are connected.

7. A luminous ionic discharge tube having an electrode made up of a series of rows of small electrode tubes separated from each other and arranged so that the group of electrode tubes is substantially rectangular in cross section.

8. A luminous ionic discharge tube having an electrode made up of a series of rows of small electrode tubes separated from each other and arranged to permit cooling air to pass between them, said dischargetube having been annealed after the electrode tubes were connected thereto.

9. A luminous ionic discharge tube having an electrode made up of a series of rows of small electrode tubes separated from each other and arranged to permit cooling air to pass between them, said electrode tubes being tubes about twenty centimeters long and five millimeters external diameter.

10. A luminous ionic discharge tube comprising a multiplicity of small electrode tubes at the terminals in sets, containing a mixture of oxides of carbon and other gases and headers to-which said sets are connected.

11. A luminous ionic discharge tube comprising a multiplicity of small electrode tubes at the terminals in sets, containing a mixture of oxides of carbon and helium and headers to which said sets are connected.

12. A luminous ionic discharge tube comprising a multiplicity of small electrode tubes at the terminals covered with conducting material having a melting point below the fusing point of said tubes.

13. A luminous ionic discharge tube comprising a multiplicity of small electrode tubes at the terminals covered with metal having a melting point below the fusing point of said tubes.

14. 'A luminous ionic discharge tube comprising a multiplicity of small electrode tubes at the terminals covered with lead and lacquer.

JOS. E. HENDERSON. BROUSSAIS C. BECK. 

